As part of such a monitoring, a monitoring device is first described in DE A 42 40 094, wherein both the respective instantaneous progression of the conveyor belt with respect to the carrier frameworks of the belt conveyor and the exact location of the bulk material on the conveyor belt should be determined. A recognition in good time of a misalignment of the conveyor should thus be detectable, on the one hand, to avoid damage to the conveyor belt and, on the other hand, a uniform loading of the conveyor belt should be ensured, by a filling chute for example, in order, for example, to prevent wear of the conveyor belt due to uneven loading and/or to prevent contamination of the belt conveyor due to falling bulk material. The known device comprises a light source that projects a strip of light onto the material flow, with an additional camera detecting an upper edge extent of both the conveyor belt and of the bulk material disposed thereon imaged hereby and with an associated image evaluation unit subsequently analyzing the upper edge extent. In this respect, the image signals recorded by the camera are digitized so that each picture element can be associated with a gray shade or with a color shade. Two sequential images are respectively subtracted, with bounding picture elements in a differential imaged detected in this manner such as side edges of the conveyor belt or load boundaries of the bulk material support being bundled to form lines of the width of a picture element. The most probably boundary lines are determined as marginal lines of the conveyor belt and of the bulk material disposed thereon and are used for determining the distance of the side edges of the conveyor belt from the carrier framework and for determining the distances between the belt edges and the bulk material edges.
The disadvantage is associated with the known device that the device has a very complex design and is additionally extremely prone to disturbance. In addition, there is the fact that the upper edge extent of the load can in particular only be determined insufficiently with heterogeneous bulk material having small, medium-size, or very large bulk material pieces. The accuracy of the image detection is additionally dependent on the respective environmental conditions such as dust content or moisture content in the environmental air and to this extent the analysis by means of the image evaluation unit suffers from large error sources.
A method is furthermore described with respect to wear monitoring in DE 100 48 552 A1 in which an optoelectronic system having a camera that should optically detect damage to the surface of the conveyor belt is installed in a region in which no bulk material support can be registered, preferably in the region of a bend pulley of the belt conveyor. For the simultaneous localization of damage found, a radar antenna combination is likewise preferably arranged in the region of the bend pulley; it is oriented on the surface of the conveyor belt and detects metal particles vulcanized at intervals in the longitudinal and/or transverse directions in addition to the reinforcement materials vulcanized in the conveyor belt.
The disadvantage is in turn associated with this prior art that the actual wear monitoring takes place by means of a camera whose recording accuracy, in particular in dependence on the external operating conditions, is not sufficient. The radar technology in this connection only serves as an aid for localizing damage to the conveyor belt recorded by the camera.